Magnetic field driven liquid crystal patterning control system

ABSTRACT

Various embodiments set forth liquid crystal (LC) patterning control systems in which LCs are aligned using locally applied magnetic fields. The index of refraction experienced by light propagating through an anisotropic LC is dependent on orientation. As a result, a phase difference may be imparted to an optical beam that is passed through, or reflected from, an array of LCs whose orientations are controlled via locally applied magnetic fields. In some embodiments, the locally applied magnetic fields may be generated by driving currents through wires that intersect at micro or nanomagnetic particles or at magnetic domains, or by applying voltages to micro or nanocoils wrapped around high-permeability cores, among other things.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application titled,“MAGNETIC FIELD DRIVEN LIQUID CRYSTAL PATTERNING CONTROL SYSTEM,” filedon Sep. 5, 2019, and having Ser. No. 16/561,258. The subject matter ofthis related application is hereby incorporated herein by reference.

BACKGROUND Field of the Various Embodiments

Embodiments of this disclosure relate generally to optical systems and,more specifically, to liquid crystal patterning control systems.

Description of the Related Art

Various liquid crystal (LC) devices use electric fields to reorientanisotropic LC molecules. In such devices, a LC in each LC cell,corresponding to a pixel, is controlled by a locally applied electricfield.

Stray electric fields from electronics tend to distort the alignment ofLCs in traditional LC devices, limiting the smallest pixel sizes of suchdevices. The performance of traditional LC devices can also degrade overtime due to ionic shielding, in which the electric fields applied toreorient LC molecules are affected by the buildup of electric fieldsfrom ion impurities within the LC itself. Such ion impurities may beproduced by, e.g., ultraviolet light breaking down the LC into ions. Inaddition, continuous power dissipation is required to maintain theelectric fields needed to align LC molecules in traditional LC devices.

SUMMARY

One embodiment of the present disclosure sets forth a liquid crystalpatterning control system including a plurality of pixels. Each of thepixels includes a liquid crystal and a magnet. Responsive to a switchingof the magnet, molecules of the liquid crystal reorient to substantiallyalign with a magnetic field generated by the magnet.

Another embodiment of the present disclosure sets forth a cell thatincludes a birefringent material and at least one alignment layerdisposed adjacent to the birefringent material. Reorientation ofmolecules in the birefringent material is driven by a magnet.

Another embodiment of the present disclosure sets forth a method formodulating light. The method includes determining states of a pluralityof pixels for at least one point in time. The method further includesdriving liquid crystals associated with the pixels using magneticfields, based on the determined states of the pixels. In addition, themethod includes projecting light that passes through the liquidcrystals.

One advantage of the liquid crystal patterning control systems disclosedherein is that the use of magnetic, rather than electric, fields toalign liquid crystals permits pixel sizes to be reduced to below thelimit of traditional liquid crystal devices. For example, the pixelsizes of embodiments may be smaller than ˜1 μm, such as ˜100 nm. Theliquid crystal patterning control systems disclosed herein are also notaffected by ionic shielding. In addition, the magnetization ofanisotropic magnets may be fixed after such magnets are switched,allowing liquid crystals to remain aligned with magnetic fields producedby those magnets without power dissipation. These technical advantagesrepresent one or more technological advancements over prior artapproaches.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the variousembodiments can be understood in detail, a more particular descriptionof the disclosed concepts, briefly summarized above, may be had byreference to various embodiments, some of which are illustrated in theappended drawings. It is to be noted, however, that the appendeddrawings illustrate only typical embodiments of the disclosed conceptsand are therefore not to be considered limiting of scope in any way, andthat there are other equally effective embodiments.

FIG. 1A is a diagram of a near eye display (NED), according to variousembodiments.

FIG. 1B is a cross section of the front rigid body of the embodiments ofthe NED illustrated in FIG. 1A.

FIG. 2A is a diagram of a head-mounted display (HMD) implemented as aNED, according to various embodiments.

FIG. 2B is a cross-section view of the HMD of FIG. 2A implemented as anear eye display, according to various embodiments.

FIG. 3 is a block diagram of a NED system, according to variousembodiments.

FIG. 4 is a schematic diagram illustrating an approach for reorientingliquid crystals (LCs) using magnetic fields, according to variousembodiments.

FIG. 5A is a schematic diagram illustrating a cross-section view of a LCpatterning control system, according to various embodiments.

FIG. 5B is a schematic diagram illustrating a top-down view of the LCpatterning control system shown in FIG. 5A, according to variousembodiments.

FIG. 6A is a schematic diagram illustrating a cross-section view ofanother LC patterning control system, according to various embodiments.

FIG. 6B is a schematic diagram illustrating a top-down view of the LCpatterning control system shown in FIG. 6A, according to variousembodiments.

FIG. 7A is a schematic diagram illustrating a cross-section view ofanother LC patterning control system, according to various embodiments.

FIG. 7B is a schematic diagram illustrating a top-down view of the LCpatterning control system shown in FIG. 7A, according to variousembodiments.

FIG. 8A is a schematic diagram illustrating a cross-section view ofanother LC patterning control system, according to various embodiments.

FIG. 8B is a schematic diagram illustrating a top-down view of the LCpatterning control system shown in FIG. 8A, according to variousembodiments.

FIG. 9 is a schematic diagram illustrating a portion of a virtualreality optical system that includes a LC patterning control system,according to various embodiments.

FIG. 10 is a schematic diagram illustrating a portion of another virtualreality optical system that includes a LC patterning control system,according to various embodiments.

FIG. 11 is a schematic diagram illustrating a portion of an augmentedreality optical system that includes a LC patterning control system,according to various embodiments.

FIG. 12A illustrates a Pancharatnam-Berry phase (PBP) grating, accordingto various embodiments.

FIG. 12B is a top-down view of an example PBP lens, according to variousembodiments.

FIG. 13 is a flow diagram illustrating a method for modulating a beam oflight, according to various embodiments.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth toprovide a more thorough understanding of the various embodiments.However, it is apparent to one of skilled in the art that the disclosedconcepts may be practiced without one or more of these specific details.

Configuration Overview

One or more embodiments disclosed herein relate to liquid crystal (LC)patterning control systems in which LCs are aligned using locallyapplied magnetic fields. The index of refraction experienced by lightpropagating through an anisotropic LC is dependent on orientation. As aresult, a phase difference may be imparted to an optical beam that ispassed through, or reflected from, an array of LCs whose orientationsare controlled via locally applied magnetic fields. In some embodiments,the locally applied magnetic fields may be generated by, e.g., drivingcurrents through wires that intersect at micro or nanomagnetic particlesor at magnetic domains, or by applying voltages to micro or nanocoilswrapped around high-permeability cores. Further, the LC patterningcontrol systems disclosed herein may be used as spatial lightmodulators, Pancharatnam-Berry phase (PBP) lenses, liquid crystaldisplay (LCD) screens, varifocal lenses, and in holography (e.g.,polarization volume holograms, point source holograms, Fourier transformholograms, or other computer-generated holograms), among other things.

Embodiments of the disclosure may also include or be implemented inconjunction with an artificial reality system. Artificial reality is aform of reality that has been adjusted in some manner beforepresentation to a user, which may include, for example, a virtualreality (VR) system, an augmented reality (AR) system, a mixed reality(MR) system, a hybrid reality system, or some combination and/orderivatives thereof. Artificial reality content may include, withoutlimitation, completely generated content or generated content combinedwith captured (e.g., real-world) content. The artificial reality contentmay include, without limitation, video, audio, haptic feedback, or somecombination thereof. The artificial reality content may be presented ina single channel or in multiple channels (such as stereo video thatproduces a three-dimensional effect to the viewer). Additionally, insome embodiments, artificial reality systems may also be associated withapplications, products, accessories, services, or some combinationthereof, that are used to, e.g., create content in an artificial realitysystem and/or are otherwise used in (e.g., perform activities in) anartificial reality system. The artificial reality system may beimplemented on various platforms, including a head-mounted display (HMD)connected to a host computer system, a standalone HMD, a mobile deviceor computing system, or any other hardware platform capable of providingartificial reality content to one or more viewers.

System Overview

FIG. 1A is a wire diagram of a near eye display (NED) 100, according tovarious embodiments. Although NEDs and head mounted displays (HMDs) aredisclosed herein as reference examples, display devices that includeliquid crystal (LC) patterning control systems in which LCs are alignedusing locally applied magnetic fields may also be configured forplacement in proximity of an eye or eyes of the user at a fixedlocation, without being head-mounted (e.g., the display device may bemounted in a vehicle, such as a car or an airplane, for placement infront of an eye or eyes of the user).

As shown, the NED 100 includes a front rigid body 105 and a band 110.The front rigid body 105 includes one or more electronic displayelements of an electronic display (not shown), an inertial measurementunit (IMU) 115, one or more position sensors 120, and locators 125. Asillustrated in FIG. 1A, position sensors 120 are located within the IMU115, and neither the IMU 115 nor the position sensors 120 are visible tothe user. In various embodiments, where the NED 100 acts as an AR or MRdevice, portions of the NED 100 and/or its internal components are atleast partially transparent.

FIG. 1B is a cross section 160 of the front rigid body 105 of theembodiments of the NED 100 illustrated in FIG. 1A. As shown, the frontrigid body 105 includes an electronic display 130 and an optics block135 that together provide image light to an exit pupil 145. The exitpupil 145 is the location of the front rigid body 105 where a user's eye140 may be positioned. For purposes of illustration, FIG. 1B illustratesa cross section 160 associated with a single eye 140, but another opticsblock, separate from the optics block 135, may provide altered imagelight to another eye of the user. Additionally, the NED 100 includes aneye tracking system (not shown in FIG. 1B). The eye tracking system mayinclude one or more sources that illuminate one or both eyes of theuser. The eye tracking system may also include one or more cameras thatcapture images of one or both eyes of the user to track the positions ofthe eyes.

The electronic display 130 displays images to the user. In variousembodiments, the electronic display 130 may comprise a single electronicdisplay or multiple electronic displays (e.g., a display for each eye ofa user). Examples of the electronic display 130 include: a liquidcrystal display (LCD), an organic light emitting diode (OLED) display,an active-matrix organic light-emitting diode display (AMOLED), a QOLED,a QLED, some other display, or some combination thereof.

The optics block 135 adjusts an orientation of image light emitted fromthe electronic display 130 such that the electronic display 130 appearsat particular virtual image distances from the user. The optics block135 is configured to receive image light emitted from the electronicdisplay 130 and direct the image light to an eye-box associated with theexit pupil 145. The image light directed to the eye-box forms an imageat a retina of eye 140. The eye-box is a region defining how much theeye 140 moves up/down/left/right from without significant degradation inthe image quality. In the illustration of FIG. 1B, a field of view (FOV)150 is the extent of the observable world that is seen by the eye 140 atany given moment.

Additionally, in some embodiments, the optics block 135 magnifiesreceived light, corrects optical errors associated with the image light,and presents the corrected image light to the eye 140. The optics block135 may include one or more optical elements 155 in optical series. Anoptical element 155 may be an aperture, a Fresnel lens, a convex lens, aconcave lens, a filter, a waveguide, a PBP lens or grating, acolor-selective filter, a waveplate, a C-plate, or any other suitableoptical element 155 that affects the image light. Moreover, the opticsblock 135 may include combinations of different optical elements. One ormore of the optical elements in the optics block 135 may have one ormore coatings, such as anti-reflective coatings. In some embodiments,the optics block 135 may include one or more of the LC patterningcontrol systems discussed in detail below in conjunction with FIGS.4-12.

FIG. 2A is a diagram of an HMD 162 implemented as a NED, according tovarious embodiments. As shown, the HMD 162 is in the form of a pair ofaugmented reality glasses. The HMD 162 presents computer-generated mediato a user and augments views of a physical, real-world environment withthe computer-generated media. Examples of computer-generated mediapresented by the HMD 162 include one or more images, video, audio, orsome combination thereof. In some embodiments, audio is presented via anexternal device (e.g., speakers and headphones) that receives audioinformation from the HMD 162, a console (not shown), or both, andpresents audio data based on audio information. In some embodiments, theHMD 162 may be modified to also operate as a virtual reality (VR) HMD, amixed reality (MR) HMD, or some combination thereof. The HMD 162includes a frame 175 and a display 164. As shown, the frame 175 mountsthe near eye display to the user's head, while the display 164 providesimage light to the user. The display 164 may be customized to a varietyof shapes and sizes to conform to different styles of eyeglass frames.

FIG. 2B is a cross-section view of the HMD 162 of FIG. 2A implemented asa NED, according to various embodiments. This view includes frame 175,display 164 (which comprises a display assembly 180 and a display block185), and eye 170. The display assembly 180 supplies image light to theeye 170. The display assembly 180 houses display block 185, which, indifferent embodiments, encloses the different types of imaging opticsand redirection structures. For purposes of illustration, FIG. 2B showsthe cross section associated with a single display block 185 and asingle eye 170, but in alternative embodiments not shown, anotherdisplay block, which is separate from display block 185 shown in FIG.2B, provides image light to another eye of the user.

The display block 185, as illustrated, is configured to combine lightfrom a local area with light from computer generated image to form anaugmented scene. The display block 185 is also configured to provide theaugmented scene to the eyebox 165 corresponding to a location of theuser's eye 170. The display block 185 may include, for example, awaveguide display, a focusing assembly, a compensation assembly, or somecombination thereof.

HMD 162 may include one or more other optical elements between thedisplay block 185 and the eye 170. The optical elements may act to, forexample, correct aberrations in image light emitted from the displayblock 185, magnify image light emitted from the display block 185, someother optical adjustment of image light emitted from the display block185, or some combination thereof. The example for optical elements mayinclude an aperture, a Fresnel lens, a convex lens, a concave lens, afilter, or any other suitable optical element that affects image light.In some embodiments, the optical elements may include one or more of theLC patterning control systems discussed in detail below in conjunctionwith FIGS. 4-12. The display block 185 may also comprise one or morematerials (e.g., plastic, glass, etc.) with one or more refractiveindices that effectively minimize the weight and widen a field of viewof the HMD 162.

FIG. 3 is a block diagram of an embodiment of a near eye display system300 in which a console 310 operates. In some embodiments, the NED system300 corresponds to the NED 100 or the HMD 162. The NED system 300 mayoperate in a virtual reality (VR) system environment, an augmentedreality (AR) system environment, a mixed reality (MR) systemenvironment, or some combination thereof. The NED system 300 shown inFIG. 3 comprises a NED 305 and an input/output (I/O) interface 315 thatis coupled to the console 310.

While FIG. 3 shows an example NED system 300 including one NED 305 andone I/O interface 315, in other embodiments any number of thesecomponents may be included in the NED system 300. For example, there maybe multiple NEDs 305 that each has an associated I/O interface 315,where each NED 305 and I/O interface 315 communicates with the console310. In alternative configurations, different and/or additionalcomponents may be included in the NED system 300. Additionally, variouscomponents included within the NED 305, the console 310, and the I/Ointerface 315 may be distributed in a different manner than is describedin conjunction with FIG. 3 in some embodiments. For example, some or allof the functionality of the console 310 may be provided by the NED 305.

The NED 305 may be a head-mounted display that presents content to auser. The content may include virtual and/or augmented views of aphysical, real-world environment including computer-generated elements(e.g., two-dimensional or three-dimensional images, two-dimensional orthree-dimensional video, sound, etc.). In some embodiments, the NED 305may also present audio content to a user. The NED 305 and/or the console310 may transmit the audio content to an external device via the I/Ointerface 315. The external device may include various forms of speakersystems and/or headphones. In various embodiments, the audio content issynchronized with visual content being displayed by the NED 305.

The NED 305 may comprise one or more rigid bodies, which may be rigidlyor non-rigidly coupled together. A rigid coupling between rigid bodiescauses the coupled rigid bodies to act as a single rigid entity. Incontrast, a non-rigid coupling between rigid bodies allows the rigidbodies to move relative to each other.

As shown in FIG. 3, the NED 305 may include a depth camera assembly(DCA) 320, a display 325, an optical assembly 330, one or more positionsensors 335, an inertial measurement unit (IMU) 340, an eye trackingsystem 345, and a varifocal module 350. In some embodiments, the display325 and the optical assembly 330 can be integrated together into aprojection assembly. Various embodiments of the NED 305 may haveadditional, fewer, or different components than those listed above.Additionally, the functionality of each component may be partially orcompletely encompassed by the functionality of one or more othercomponents in various embodiments.

The DCA 320 captures sensor data describing depth information of an areasurrounding the NED 305. The sensor data may be generated by one or acombination of depth imaging techniques, such as triangulation,structured light imaging, time-of-flight imaging, laser scan, and soforth. The DCA 320 can compute various depth properties of the areasurrounding the NED 305 using the sensor data. Additionally oralternatively, the DCA 320 may transmit the sensor data to the console310 for processing.

The DCA 320 includes an illumination source, an imaging device, and acontroller. The illumination source emits light onto an area surroundingthe NED 305. In an embodiment, the emitted light is structured light.The illumination source includes a plurality of emitters that each emitslight having certain characteristics (e.g., wavelength, polarization,coherence, temporal behavior, etc.). The characteristics may be the sameor different between emitters, and the emitters can be operatedsimultaneously or individually. In one embodiment, the plurality ofemitters could be, e.g., laser diodes (such as edge emitters), inorganicor organic light-emitting diodes (LEDs), a vertical-cavitysurface-emitting laser (VCSEL), or some other source. In someembodiments, a single emitter or a plurality of emitters in theillumination source can emit light having a structured light pattern.The imaging device captures ambient light in the environment surroundingNED 305, in addition to light reflected off of objects in theenvironment that is generated by the plurality of emitters. In variousembodiments, the imaging device may be an infrared camera or a cameraconfigured to operate in a visible spectrum. The controller coordinateshow the illumination source emits light and how the imaging devicecaptures light. For example, the controller may determine a brightnessof the emitted light. In some embodiments, the controller also analyzesdetected light to detect objects in the environment and positioninformation related to those objects.

The display 325 displays two-dimensional or three-dimensional images tothe user in accordance with pixel data received from the console 310. Invarious embodiments, the display 325 comprises a single display ormultiple displays (e.g., separate displays for each eye of a user). Insome embodiments, the display 325 comprises a single or multiplewaveguide displays. Light can be coupled into the single or multiplewaveguide displays via, e.g., a liquid crystal display (LCD), an organiclight emitting diode (OLED) display, an inorganic light emitting diode(ILED) display, an active-matrix organic light-emitting diode (AMOLED)display, a transparent organic light emitting diode (TOLED) display, alaser-based display, one or more waveguides, other types of displays, ascanner, a one-dimensional array, and so forth. In addition,combinations of the displays types may be incorporated in display 325and used separately, in parallel, and/or in combination.

The optical assembly 330 magnifies image light received from the display325, corrects optical errors associated with the image light, andpresents the corrected image light to a user of the NED 305. The opticalassembly 330 includes a plurality of optical elements. For example, oneor more of the following optical elements may be included in the opticalassembly 330: an aperture, a Fresnel lens, a convex lens, a concavelens, a filter, a reflecting surface, or any other suitable opticalelement that deflects, reflects, refracts, and/or in some way altersimage light. Moreover, the optical assembly 330 may include combinationsof different optical elements. In some embodiments, one or more of theoptical elements in the optical assembly 330 may have one or morecoatings, such as partially reflective or antireflective coatings. Theoptical assembly 330 can be integrated into a projection assembly, e.g.,a projection assembly. In one embodiment, the optical assembly 330includes the optics block 155.

In operation, the optical assembly 330 magnifies and focuses image lightgenerated by the display 325. In so doing, the optical assembly 330enables the display 325 to be physically smaller, weigh less, andconsume less power than displays that do not use the optical assembly330. Additionally, magnification may increase the field of view of thecontent presented by the display 325. For example, in some embodiments,the field of view of the displayed content partially or completely usesa user's field of view. For example, the field of view of a displayedimage may meet or exceed 310 degrees. In various embodiments, the amountof magnification may be adjusted by adding or removing optical elements.

In some embodiments, the optical assembly 330 may be designed to correctone or more types of optical errors. Examples of optical errors includebarrel or pincushion distortions, longitudinal chromatic aberrations, ortransverse chromatic aberrations. Other types of optical errors mayfurther include spherical aberrations, chromatic aberrations or errorsdue to the lens field curvature, astigmatisms, in addition to othertypes of optical errors. In some embodiments, visual content transmittedto the display 325 is pre-distorted, and the optical assembly 330corrects the distortion as image light from the display 325 passesthrough various optical elements of the optical assembly 330. In someembodiments, optical elements of the optical assembly 330 are integratedinto the display 325 as a projection assembly that includes at least onewaveguide coupled with one or more optical elements.

The IMU 340 is an electronic device that generates data indicating aposition of the NED 305 based on measurement signals received from oneor more of the position sensors 335 and from depth information receivedfrom the DCA 320. In some embodiments of the NED 305, the IMU 340 may bea dedicated hardware component. In other embodiments, the IMU 340 may bea software component implemented in one or more processors.

In operation, a position sensor 335 generates one or more measurementsignals in response to a motion of the NED 305. Examples of positionsensors 335 include: one or more accelerometers, one or more gyroscopes,one or more magnetometers, one or more altimeters, one or moreinclinometers, and/or various types of sensors for motion detection,drift detection, and/or error detection. The position sensors 335 may belocated external to the IMU 340, internal to the IMU 340, or somecombination thereof.

Based on the one or more measurement signals from one or more positionsensors 335, the IMU 340 generates data indicating an estimated currentposition of the NED 305 relative to an initial position of the NED 305.For example, the position sensors 335 may include multipleaccelerometers to measure translational motion (forward/back, up/down,left/right) and multiple gyroscopes to measure rotational motion (e.g.,pitch, yaw, and roll). In some embodiments, the IMU 340 rapidly samplesthe measurement signals and calculates the estimated current position ofthe NED 305 from the sampled data. For example, the IMU 340 mayintegrate the measurement signals received from the accelerometers overtime to estimate a velocity vector and integrates the velocity vectorover time to determine an estimated current position of a referencepoint on the NED 305. Alternatively, the IMU 340 provides the sampledmeasurement signals to the console 310, which analyzes the sample datato determine one or more measurement errors. The console 310 may furthertransmit one or more of control signals and/or measurement errors to theIMU 340 to configure the IMU 340 to correct and/or reduce one or moremeasurement errors (e.g., drift errors). The reference point is a pointthat may be used to describe the position of the NED 305. The referencepoint may generally be defined as a point in space or a position relatedto a position and/or orientation of the NED 305.

In various embodiments, the IMU 340 receives one or more parameters fromthe console 310. The one or more parameters are used to maintaintracking of the NED 305. Based on a received parameter, the IMU 340 mayadjust one or more IMU parameters (e.g., a sample rate). In someembodiments, certain parameters cause the IMU 340 to update an initialposition of the reference point so that it corresponds to a nextposition of the reference point. Updating the initial position of thereference point as the next calibrated position of the reference pointhelps reduce drift errors in detecting a current position estimate ofthe IMU 340.

In some embodiments, the eye tracking system 345 is integrated into theNED 305. The eye-tracking system 345 may comprise one or moreillumination sources and an imaging device (camera). In operation, theeye tracking system 345 generates and analyzes tracking data related toa user's eyes as the user wears the NED 305. The eye tracking system 345may further generate eye tracking information that may compriseinformation about a position of the user's eye, i.e., information aboutan angle of an eye-gaze.

In some embodiments, the varifocal module 350 is further integrated intothe NED 305. The varifocal module 350 may be communicatively coupled tothe eye tracking system 345 in order to enable the varifocal module 350to receive eye tracking information from the eye tracking system 345.The varifocal module 350 may further modify the focus of image lightemitted from the display 325 based on the eye tracking informationreceived from the eye tracking system 345. Accordingly, the varifocalmodule 350 can reduce vergence-accommodation conflict that may beproduced as the user's eyes resolve the image light. In variousembodiments, the varifocal module 350 can be interfaced (e.g., eithermechanically or electrically) with at least one optical element of theoptical assembly 330.

In operation, the varifocal module 350 may adjust the position and/ororientation of one or more optical elements in the optical assembly 330in order to adjust the focus of image light propagating through theoptical assembly 330. In various embodiments, the varifocal module 350may use eye tracking information obtained from the eye tracking system345 to determine how to adjust one or more optical elements in theoptical assembly 330. In some embodiments, the varifocal module 350 mayperform foveated rendering of the image light based on the eye trackinginformation obtained from the eye tracking system 345 in order to adjustthe resolution of the image light emitted by the display 325. In thiscase, the varifocal module 350 configures the display 325 to display ahigh pixel density in a foveal region of the user's eye-gaze and a lowpixel density in other regions of the user's eye-gaze.

The I/O interface 315 facilitates the transfer of action requests from auser to the console 310. In addition, the I/O interface 315 facilitatesthe transfer of device feedback from the console 310 to the user. Anaction request is a request to perform a particular action. For example,an action request may be an instruction to start or end capture of imageor video data or an instruction to perform a particular action within anapplication, such as pausing video playback, increasing or decreasingthe volume of audio playback, and so forth. In various embodiments, theI/O interface 315 may include one or more input devices. Example inputdevices include: a keyboard, a mouse, a game controller, a joystick,and/or any other suitable device for receiving action requests andcommunicating the action requests to the console 310. In someembodiments, the I/O interface 315 includes an IMU 340 that capturescalibration data indicating an estimated current position of the I/Ointerface 315 relative to an initial position of the I/O interface 315.

In operation, the I/O interface 315 receives action requests from theuser and transmits those action requests to the console 310. Responsiveto receiving the action request, the console 310 performs acorresponding action. For example, responsive to receiving an actionrequest, the console 310 may configure the I/O interface 315 to emithaptic feedback onto an arm of the user. For example, the console 315may configure the I/O interface 315 to deliver haptic feedback to a userwhen an action request is received. Additionally or alternatively, theconsole 310 may configure the I/O interface 315 to generate hapticfeedback when the console 310 performs an action, responsive toreceiving an action request.

The console 310 provides content to the NED 305 for processing inaccordance with information received from one or more of: the DCA 320,the NED 305, and the I/O interface 315. As shown in FIG. 3, the console310 includes an application store 355, a tracking module 360, and anengine 365. In some embodiments, the console 310 may have additional,fewer, or different modules and/or components than those described inconjunction with FIG. 3. Similarly, the functions further describedbelow may be distributed among components of the console 310 in adifferent manner than described in conjunction with FIG. 3.

The application store 355 stores one or more applications for executionby the console 310. An application is a group of instructions that, whenexecuted by a processor, performs a particular set of functions, such asgenerating content for presentation to the user. For example, anapplication may generate content in response to receiving inputs from auser (e.g., via movement of the NED 305 as the user moves his/her head,via the I/O interface 315, etc.). Examples of applications include:gaming applications, conferencing applications, video playbackapplications, or other suitable applications.

The tracking module 360 calibrates the NED system 300 using one or morecalibration parameters. The tracking module 360 may further adjust oneor more calibration parameters to reduce error in determining a positionand/or orientation of the NED 305 or the I/O interface 315. For example,the tracking module 360 may transmit a calibration parameter to the DCA320 in order to adjust the focus of the DCA 320. Accordingly, the DCA320 may more accurately determine positions of structured light elementsreflecting off of objects in the environment. The tracking module 360may also analyze sensor data generated by the IMU 340 in determiningvarious calibration parameters to modify. Further, in some embodiments,if the NED 305 loses tracking of the user's eye, then the trackingmodule 360 may re-calibrate some or all of the components in the NEDsystem 300. For example, if the DCA 320 loses line of sight of at leasta threshold number of structured light elements projected onto theuser's eye, the tracking module 360 may transmit calibration parametersto the varifocal module 350 in order to re-establish eye tracking.

The tracking module 360 tracks the movements of the NED 305 and/or ofthe I/O interface 315 using information from the DCA 320, the one ormore position sensors 335, the IMU 340 or some combination thereof. Forexample, the tracking module 360 may determine a reference position ofthe NED 305 from a mapping of an area local to the NED 305. The trackingmodule 360 may generate this mapping based on information received fromthe NED 305 itself. The tracking module 360 may also utilize sensor datafrom the IMU 340 and/or depth data from the DCA 320 to determinereferences positions for the NED 305 and/or I/O interface 315. Invarious embodiments, the tracking module 360 generates an estimationand/or prediction for a subsequent position of the NED 305 and/or theI/O interface 315. The tracking module 360 may transmit the predictedsubsequent position to the engine 365.

The engine 365 generates a three-dimensional mapping of the areasurrounding the NED 305 (i.e., the “local area”) based on informationreceived from the NED 305. In some embodiments, the engine 365determines depth information for the three-dimensional mapping of thelocal area based on depth data received from the DCA 320 (e.g., depthinformation of objects in the local area). In some embodiments, theengine 365 calculates a depth and/or position of the NED 305 by usingdepth data generated by the DCA 320. In particular, the engine 365 mayimplement various techniques for calculating the depth and/or positionof the NED 305, such as stereo based techniques, structured lightillumination techniques, time-of-flight techniques, and so forth. Invarious embodiments, the engine 365 uses depth data received from theDCA 320 to update a model of the local area and to generate and/ormodify media content based in part on the updated model.

The engine 365 also executes applications within the NED system 300 andreceives position information, acceleration information, velocityinformation, predicted future positions, or some combination thereof, ofthe NED 305 from the tracking module 360. Based on the receivedinformation, the engine 365 determines various forms of media content totransmit to the NED 305 for presentation to the user. For example, ifthe received information indicates that the user has looked to the left,the engine 365 generates media content for the NED 305 that mirrors theuser's movement in a virtual environment or in an environment augmentingthe local area with additional media content. Accordingly, the engine365 may generate and/or modify media content (e.g., visual and/or audiocontent) for presentation to the user. The engine 365 may furthertransmit the media content to the NED 305. Additionally, in response toreceiving an action request from the I/O interface 315, the engine 365may perform an action within an application executing on the console310. The engine 305 may further provide feedback when the action isperformed. For example, the engine 365 may configure the NED 305 togenerate visual and/or audio feedback and/or the I/O interface 315 togenerate haptic feedback to the user.

In some embodiments, based on the eye tracking information (e.g.,orientation of the user's eye) received from the eye tracking system345, the engine 365 determines a resolution of the media contentprovided to the NED 305 for presentation to the user on the display 325.The engine 365 may adjust a resolution of the visual content provided tothe NED 305 by configuring the display 325 to perform foveated renderingof the visual content, based at least in part on a direction of theuser's gaze received from the eye tracking system 345. The engine 365provides the content to the NED 305 having a high resolution on thedisplay 325 in a foveal region of the user's gaze and a low resolutionin other regions, thereby reducing the power consumption of the NED 305.In addition, using foveated rendering reduces a number of computingcycles used in rendering visual content without compromising the qualityof the user's visual experience. In some embodiments, the engine 365 canfurther use the eye tracking information to adjust a focus of the imagelight emitted from the display 325 in order to reducevergence-accommodation conflicts.

Magnetic Field Driven Reorientation of Liquid Crystals in a LiquidCrystal Patterning Control System

FIG. 4 is a schematic diagram illustrating an approach for reorientingliquid crystals (LCs) using magnetic fields, according to variousembodiments. Panel A shows the geometry associated with a pixel 400 of aLC patterning control system that uses magnetic fields to drive thereorientation of LCs. As used herein, a pixel refers to a LC cell, whichmay include a LC and alignment layer(s), along with a drive method, suchas a magnet. In some embodiments, dividers are not required betweenpixels or cells, although dividers may be used in other embodiments. Forexample, in an embodiment without dividers, a magnet that reorients aportion of a LC layer may be considered one cell, another magnet thatreorients a different portion of the LC layer may be considered a nextcell, etc.

As shown, the pixel 400 includes a LC layer 404 between two alignmentlayers 402 and 406, a reflective layer 408, and a magnet 410. Althoughone pixel 400 is shown for illustrative purposes, a LC patterningcontrol system may generally include any number of pixels, such as anarray of pixels. The pixels in some embodiments may also includeadditional, or different, layers than those shown, such as glasssubstrate layers surrounding the alignment layers 402 and 406,polarization layers on one or both sides of the glass substrate layers,etc. Although FIG. 4 shows a reflective LC patterning control system,LCs may also be reoriented using magnetic fields in transmissive LCpatterning control systems in some embodiments, as discussed below.

Liquid crystals are birefringent, meaning the refractive index of a LCdepends on orientation. In some embodiments, the LC layer 404 mayinclude a uniaxial nematic LC having an ordinary refractive index alongan optical axis, sometimes referred to as the “director,” with whichanisotropic molecules 405 _(i) (collectively referred to as molecules405 and individually referred to as molecule 405) of the LC layer 404are aligned, as well as an extraordinary refractive index along adirection perpendicular to the optical axis. In such cases, a magneticfield may be applied to reorient the optical axis, thereby changing therefractive index with respect to light incident on the LC layer 404. Asa result, a phase of light passing through the LC layer 404 will bemodulated differently when the magnetic field is applied than when no(or a different) magnetic field is applied, which may representdifferent states of the pixel 400 (e.g., ON and OFF states). Otherembodiments may use any technically feasible type of LC, includingchiral nematic LCs (also sometimes referred to as LCs in the“cholesteric” phase), biaxial nematic LCs, etc. It should be understoodthat the response to a magnetic field may vary depending on the type ofLC used.

Although discussed herein primarily with respect to phase modulation, insome embodiments, a LC patterning control system may be used to modulatethe amplitude of light in addition to, or in lieu, to modulating thephase of light. For example, a set of crossed polarizers including alinear polarizer for polarizing light that is input into a LC at 45° andan analyzer that transmits a component of light output by the LC couldbe used in some embodiments to control the transmission of light. Otheramplitude modulation schemes may be used in alternative embodiments.Although discussed herein primarily with respect to LCs, birefringentmaterials other than LCs may be used in some embodiments.

As shown, the alignment layers 402 and 406 induce the molecules 405 ofthe LC layer 404 into a substantially uniform planar alignment. In someembodiments, the alignment layers 402 and 406 may be formed by rubbingpolymer surfaces. More generally, any technically feasible process maybe used to align the molecules 405 of the LC layer 404. Although aplanar alignment is shown for illustrative purposes, embodiments mayinclude LCs with any suitable alignment, such as a homeotropic alignmentin which LC molecules are aligned perpendicular to the alignment layers402 and 406.

As shown in panel B, application of a magnetic field 412 reorients theLC molecules 405 by aligning them with the magnetic field 412, which issubstantially uniform except for fringe fields at the sides of themagnet 410. It should be understood that the magnetic field 412 may alsoextend elsewhere, such as inside the magnet 410, but such portions ofmagnetic fields are not shown herein for simplicity. Further, it shouldbe understood that some LC molecules 405 may not be completely alignedwith the magnetic field 412, and the degree of alignment achieved maygenerally depend on, e.g., the LC material used to construct the LClayer 404 and the strength of the magnetic field 412. Illustratively, anarea of the LC layer 404 is smaller than an area of the magnet 410. As aresult, the LC molecules 405 are substantially unaffected by the fringefield. Upon application of the magnetic field 412, the LC molecules 405are reoriented from a planar alignment to a direction perpendicular tothe plane by a substantially uniform part of the magnetic field 412 thatis generated by the magnet 410.

In operation, light from one or more light emission devices may beincident on a LC patterning control system comprising an array ofpixels, including the pixel 400. Polarized light may be used in someembodiments. In other embodiments, the LC patterning control system maywork equally well on both polarizations. In general, the LC patterningcontrol system may be, e.g., a spatial light modulator, aPancharatnam-Berry phase (PBP) lens, a liquid crystal display (LCD)screen, a varifocal lens, or used in holography (e.g., polarizationvolume holograms, point source holograms, Fourier transform holograms,or other computer-generated holograms), among other things. Bycontrolling the states of pixels in the LC patterning control system, aspatially varying modulation may be imposed on the light, with themodulated light being reflected back by the reflective layer 408. Forexample, pixels of a spatial light modulator could be switched ON andOFF, thereby forming image(s) reflected toward a viewer. As anotherexample, to generate a hologram, holography equations could be solved inorder to determine pixel states needed to generate the hologram fromlight emitted by a coherent light source, such as a laser. Additionaland further examples are discussed in greater detail below.

FIG. 5A is a schematic diagram illustrating a cross-section view of a LCpatterning control system 500, according to various embodiments. Asshown, the LC patterning control system 500 includes an array of pixelscomprising respective LCs 5021 to 502N (collectively referred to as LCs502 and individually referred to as LC 502) and corresponding magnets5061 to 506N (collectively referred to as magnets 506 and individuallyreferred to as magnet 506). All or some of the components of the LCpatterning control system 500 may be in physical contact with oneanother, share a substrate with one another, laminated with one another,optically in contact with one another, have index matching fluid oroptical glue between one another, and/or may have space therebetween.

The LCs 502 and magnets 506 may be constructed from any technicallyfeasible materials. As described, the LCs 502 may include any suitabletype of LCs, such as uniaxial nematic LCs, chiral nematic LCs, biaxialnematic LCs, etc. In some embodiments, the magnets 506 may includemagnetic micro or nanoparticles. Patterned magnetic multilayer films, orperpendicularly magnetized films, may be used in some embodiments. Small(<1 μm) magnetic particles are capable of generating external magneticfields over the critical field H_(c) required to reorient some LCs. Forexample, some nanomagnets can generate magnetic fields on the order of˜1-2 T, which is sufficient to completely align some LCs. The fieldsgenerated by a small magnetic particle extends a distance ˜d, where d isa characteristic dimension of the particle. The magnetic particles 506may be of any suitable shape and/or size, including particles of size 50nm and smaller. The LCs 502 may also be of any suitable shape and/orsize. For example, in some embodiments, each of the LCs 502 may be a fewhundred nanometers thick. In some embodiments, the sizes of pixels inthe LC patterning control system 500 may be reduced to below the limitof traditional LC devices that rely on electric fields, including pixelsizes of less than ˜1 μm.

In some embodiments, the magnets 506 may be anisotropic. That is, themagnets 506 may have multiple preferred magnetization directions, whichare also sometimes referred to as “easy axes.” For example, in someembodiments, each of the magnets 506 may have two easy axes, such as onein the plane and another perpendicular to the plane (as shown in FIGS.5A-5B) or two in the plane at orthogonal angles. Further, themagnetization direction of a magnet 506 may remain stable after aligningwith one of the easy axes. Such an existence of two stable equilibriumstates is referred to as bistability.

The LC patterning control system 500 further includes a reflective layer504 and a grid of wires 5081 to 508N (collectively referred to as wires508 and individually referred to as wire 508) and 510, which arediscussed in greater detail below with respect to FIG. 5B. Althoughparticular layers are shown for illustrative purposes, some embodimentsmay include additional layers, such as alignment layers and glasssubstrate layers surrounding each of the LCs 502, polarization layers onone or both sides of the glass substrate layers, etc., similar to thediscussion above with respect to FIG. 4.

Light incident on the LC patterning control system 500 may pass throughthe LCs 502 and be reflected by the reflective layer 504 toward, e.g., aviewer or optical element(s) such as a lens. That is, the LC patterningcontrol system 500 acts as a mirror, with LCs 502 that modulate lightincident thereon to generate a spatially varying modulation of light. Asdescribed, the light that is projected onto the LC patterning controlsystem 500 may also be polarized in some embodiments.

In some embodiments, gaps between the magnets 506, such as the gap 5071,may be covered by a reflective material, and the reflective layer 504may be formed by sputtering the reflective material, such as chrome, ontop of the magnets 506 and the gaps. Doing so may eliminate diffractionthat would otherwise be produced by the gaps.

FIG. 5B is a schematic diagram illustrating a top-down view of the LCpatterning control system 500, according to various embodiments. Asshown, the wires 508 and 510 are disposed in a crossed-wire scheme belowthe magnets 506 and the LCs 502. The reflective layer 504 above themagnets 506 has been omitted for illustrative purposes.

As shown, respective pairs of the wires 508 and 510 cross at each of theLCs 502. Magnetic fields are generated by the flowing of current throughthe wires 508 and 510. For example, thin-film transistors could be usedto drive currents through the wires 508 and 510. The magnetic fieldgenerated by the flowing of current through a wire is H˜l/r, where l isthe current in the wire and r is the distance from the wire. By usingmagnets 506 for which the coercive field required to switch the magnets506 is ˜2l/r, two of the wires 508 and 510 can be driven at the sametime to generate the coercive field needed to switch one of the magnets506 between, e.g., different easy axes where the magnets 506 areanisotropic. Returning to the example above in which each of the magnets506 has two easy axes, current may be driven through pairs of the wires508 and 510 intersecting at a magnet 506 to nudge its magnetizationtoward one of the easy axes, after which the magnetization may snap tothe easy axis direction. Further, the magnetization may remain fixed (inthe absence of additional currents being driven through the wires 508and 510) without power dissipation, in contrast to traditional LCdevices that require continuous power dissipation to maintain theelection fields for aligning LCs. Current may thereafter be driventhrough the same wires, but in the opposite directions, to switch themagnet back to its other easy axis, thereby reversing the direction ofthe magnetic field.

For example, a magnet 5061 could be switched by driving current throughboth of the wires 5081 and 5101 that intersect at the magnet 5061. Insuch a case, twice the magnetic field of a wire is generated at theintersection, while magnets 506 above only one of the wires 5081 and5101 would only see the magnetic field associated with that wire. Forexample, magnetization of the magnets 506 may initially be in the plane,and the magnetization of the magnet 5061 may be switched to produce amagnetic field that is perpendicular to the plane, as shown in FIG. 5B.Anisotropic molecules of the LC 5021 may reorient to align with theperpendicular magnetic field, as described above with respect to FIG. 4.Such an alignment with the magnetic field may represent, e.g., an ONstate of the pixel, while other LCs 502 (in, e.g., a planar alignment)may represent an OFF state, or vice versa. Further, the magnets 506 andassociated LCs 502 may be rapidly switched (e.g., at 10-100 ns) in someembodiments.

Although the wires 508 and 510 are shown as being disposed below andbeing thinner than the magnets 506, any technically feasibleconfiguration of wires may be used to create the coercive fields neededto switch the magnets 506. For example, in some embodiments, the wires508 and 510 may be the same thickness as the magnets 506. As anotherexample, wires may be disposed on the sides of magnets, rather thanbelow the magnets, in some embodiments. Further, although exemplarydrive schemes, such as those described with respect to FIGS. 5A-5B,6A-6B, 7A-7B, and 8A-8B, are disclosed herein for illustrative purposes,any technically feasible scheme for driving LCs using magnetic fieldsmay be employed in alternative embodiments.

FIG. 6A is a schematic diagram illustrating a cross-section view ofanother LC patterning control system 600, according to variousembodiments. As shown, the LC patterning control system 600 includes anarray of pixels comprising respective LCs 6021 to 602N (collectivelyreferred to as LCs 602 and individually referred to as LC 602), areflective layer 604, a layer 606 including magnetic domains 607 ₁ to607 _(NN) (collectively referred to as magnetic domains 607 andindividually referred to as magnetic domain 607), and wires 608 ₁ to 608_(N) (collectively referred to as wires 608 and individually referred toas wire 608) and 610. The LCs 602, the reflective layer 604, and thewires 608 and 610 are similar to the LCs 502, the reflective layer 504,and the wires 508 and 510, respectively, of the LC patterning controlsystem 500 and will not be described in detail for conciseness. All orsome of the components of the LC patterning control system 600 may be inphysical contact with one another, share a substrate with one another,laminated with one another, optically in contact with one another, haveindex matching fluid or optical glue between one another, and/or mayhave space therebetween.

A magnetic domain is a region within a magnetic material in whichmagnetization is in a uniform direction due to the magnetic moments ofatoms being aligned to point in the same direction. A continuous film ofmagnetic material in which the magnetic moments of atoms are aligned inthe same direction will not produce a magnetic field above the film.However, the magnetic fields at transitions between magnetic domains ofa magnetic film can extend above the film. In some embodiments, LCs maybe placed above such transition regions where magnetic fields extendabove a film of magnetic material.

Illustratively, the magnetic layer 606 includes magnetic domains 607with transitions below the LCs 602. For example, magnetic moments ofatoms in the magnetic domains 607 ₁ and 607 ₃ could be aligned in adifferent direction than magnetic moments of atoms in the magneticdomain 607 ₂. Although a particular configuration is shown forillustrative purposes, other configurations may be used in alternativeembodiments. Magnetic domains are generally separated by transitionregions called domain walls, and the magnetic domains 607 may beseparated by domain walls having any suitable properties (narrow orbroad, how easily they move, etc.) in some embodiments.

In some embodiments, the magnetic domains 607 may be anisotropic, withtwo (or more) easy axes along which magnetization of the magneticdomains 607 may be switched, similar to the discussion above withrespect to the magnets 506 of the LC patterning control system 500.Further, in some embodiments, the magnetic domains 607 may besufficiently small that a pixel size of the LC patterning control system600 can be reduced below the limit of traditional LC devices, includingpixel sizes of less than ˜1 μm.

FIG. 6B is a schematic diagram illustrating a top-down view of the LCpatterning control system 600, according to various embodiments. Asshown, the wires 608 and 610 are disposed in a crossed-wire scheme belowthe LCs 602 and corresponding magnetic domains, similar to the wires 508and 510 described above with respect to FIG. 5B. Magnetic fields can begenerated by the flowing of current through the wires 608 and 610. Forexample, thin-film transistors could be used to drive currents throughthe wires 608 and 610. The magnetic field generated by the flowing ofcurrent through one of the wires 608 and 610 is H˜l/r, and two of thewires 608 and 610 may be driven at the same time to generate a coercivefield ˜2l/r needed to switch one of the magnetic domains 607 between,e.g., different easy axes where the magnetic domains 607 areanisotropic, similar to the discussion above with respect to FIG. 5B.

For example, the magnet domain 607 ₂ could be switched by drivingcurrent through both of the wires 608 ₁ and 610 ₁ that intersect at themagnetic domain 607 ₂. As shown in FIGS. 6A-6B, doing so produces amagnetic field that is perpendicular to the plane. Anisotropic moleculesof the LC 6021 may reorient to align with such a magnetic field,representing, e.g., an ON state of the pixel, while LCs 602 whosemolecules are not so aligned (and in, e.g., a planar alignment) mayrepresent an OFF state, or vice versa. Similar to the magnets 506 andLCs 502 described above with respect to FIG. 5B, the magnetic domains607 and associated LCs 602 may be rapidly switched (at, e.g., 10-100 ns)in some embodiments. Further, when not being switched, magnetizations ofthe magnetic domains 607 may remain fixed without power dissipation.

Although the wires 608 and 610 are shown as being disposed below andbeing thinner than the magnetic domains 607, any technically feasibleconfiguration of wires capable of creating the coercive fields needed toswitch magnetic domains may be used, including thicker wires and wiresdisposed on the sides of magnetic domains.

FIG. 7A is a schematic diagram illustrating a cross-section view ofanother LC patterning control system 700, according to variousembodiments. As shown, the LC patterning control system 700 includes anarray of pixels comprising respective LCs 702 ₁ to 702 _(N)(collectively referred to as LCs 702 and individually referred to as LC702) and corresponding magnets 706 ₁ to 706 _(N) (collectively referredto as magnets 706 and individually referred to as magnet 706), as wellas a reflective layer 704. The LCs 702 and the reflective layer 704 aresimilar to the LCs 502 and the reflective layer 504, respectively, ofthe LC patterning control system 500 and will not be described in detailfor conciseness. All or some of the components of the LC patterningcontrol system 700 may be in physical contact with one another, share asubstrate with one another, laminated with one another, optically incontact with one another, have index matching fluid or optical gluebetween one another, and/or may have space therebetween.

As shown, each of the magnets 706 is an electromagnet comprising a highpermeability core around which a coil of wire is wrapped. In someembodiments, the coil of wire may be a micro or nanocoil. The coil ofwire and the high permeability core may be constructed from anytechnically feasible materials. For example, the high permeability corecould be an iron core. In some embodiments, the magnets 706 may besufficiently small that a pixel size of the LC patterning control system700 can be reduced below the limit of traditional LC devices, includingpixel sizes of less than ˜1 μm.

In operation, the flowing of current through the coil of wire of amagnet 706 creates a magnetic field therein. In addition, the strengthof such a magnetic field is multiplied by a permeability of the core,i.e., the field that is generated equals B=μH, where μ is thepermeability of the core and H is the field due to the current in thewire. As a result, a relatively large magnetic field can be generatedwith a relatively low current. For example, an iron core could enhancethe strength of a magnetic field by a factor of 10,000. Although themagnetic field inside the core itself is not useful, the field justoutside an end of the core is substantially equal to the field inside.As shown, each of the LCs 702 is disposed above the core of a respectivemagnet 706 so as to experience such a magnetic field just outside thecore of the magnet 706.

Respective voltages 708 ₁ to 708 _(N) (collectively referred to asvoltages 708 and individually referred to as voltage 708) may be appliedto drive currents through the coils around the magnets 706.Illustratively, application of the voltage 708 ₁ drives current throughthe coil around the magnet 706 ₁, thereby generating a magnetic field.In some embodiments, the coils around the magnets 706 may also beconnected to a common ground. For example, one end of the coil could beconnected to a voltage (+/−V) and the other to ground. Doing so drivescurrent through the coil, and switching the positive and negativevoltages (+V to −V or −V to +V) switches the direction of the magneticfield.

FIG. 7B is a schematic diagram illustrating a top-down view of the LCpatterning control system 700, according to various embodiments. Asshown, application of a voltage causes current to be driven in a coil ofthe magnet 706 ₁, thereby generating a magnetic field perpendicular tothe plane. Anisotropic molecules of the LC 702 ₁ may reorient to alignwith such a magnetic field, which may represent, e.g., an ON state ofthe pixel, while LCs 702 whose molecules are not aligned with a magneticfield (and in, e.g., a planar alignment) may represent an OFF state, orvice versa.

FIG. 8A is a schematic diagram illustrating a cross-section view ofanother LC patterning control system 800, according to variousembodiments. As shown, the LC patterning control system 800 includes anarray of pixels comprising respective LCs 802 ₁ to 802 _(N)(collectively referred to as LCs 802 and individually referred to as LC802), and corresponding magnets 804 ₁ to 804 _(N) (collectively referredto as magnets 804 and individually referred to as magnet 804). The LCs802 are similar to the LCs 502 of the LC patterning control system 500and will not be described in detail for conciseness. All or some of thecomponents of the LC patterning control system 800 may be in physicalcontact with one another, share a substrate with one another, laminatedwith one another, optically in contact with one another, have indexmatching fluid or optical glue between one another, and/or may havespace therebetween.

As shown, each of the magnets 804 is wrapped around one of the LCs 802.In some embodiments, the magnets 804 may be anisotropic, with two (ormore) easy axes along which magnetization of the magnets 804 may beswitched, similar to the discussion above with respect to the magnets506 of the LC patterning control system 500. Further, the magnets 804 insome embodiments may be sufficiently small that a pixel size of the LCpatterning control system 800 can be reduced below the limit oftraditional LC devices, including pixel sizes of less than ˜1 μm. Insome other embodiments, two or more magnets may be placed at the edge ofeach cell.

As shown, the LC patterning control system 800 also includes wires 806 ₁to 806 _(N) and 808 ₁ to 808 _(M) (collectively referred to as wires 806and 808 and individually referred to as wire 806 and 808, respectively)that are disposed in a crossed-wire scheme below the LCs 802 and magnets804. FIG. 8B is a schematic diagram illustrating a top-down view of theLC patterning control system 800 showing the cross-wire scheme. Similarto the wires 508 and 510 described above with respect to FIG. 5B,magnetic fields are generated by the flowing of current through thewires 806 and 808. For example, thin-film transistors could be used todrive currents through the wires 806 and 808, and two of the wires 806and 808 may be driven at the same time to generate a coercive fieldneeded to switch one of the magnets 804 between, e.g., different easyaxes in the case of anisotropic magnets 804.

As shown in FIGS. 7A-7B, the switching of the magnet 804 ₁, by drivingcurrent through both of the wires 806 ₁ and 808 ₁, produces a magneticfield that is in a particular direction in the plane. Anisotropicmolecules of the LC 802 ₁ may reorient to align with such a magneticfield, which may represent, e.g., an ON state of the pixel, while themolecules of other LCs 802 may be aligned in another direction (e.g.,perpendicular to the plane) and represent an OFF state, or vice versa.Similar to the magnets 506 and LCs 502 described above with respect toFIG. 5B, the magnets 804 and associated LCs 802 may be rapidly switchedat, e.g., 10-100 ns per switch in some embodiments. Further, when notbeing switched, magnetizations of the magnets 804 may remain fixedwithout power dissipation.

Although certain embodiments of reflective and transmissive LCpatterning control systems are described above with respect to FIGS. 4-8as reference examples, other embodiments in which magnetic fields areused to align LCs are also contemplated. For example, in someembodiments, the orientations of magnetic fields generated by magnetsmay differ from the examples disclosed herein. As another example,transparent magnetic oxides may be used in some transmissive embodimentsin lieu of magnets that wrap around LCs.

FIGS. 9-10 illustrate example optical system configurations that includeone or more LC patterning control systems, according to variousembodiments. Such systems may be included in, for example, near-eyedisplay devices for virtual reality (VR), augmented reality (AR), ormixed reality (MR), such as the such as the NED system 100 or the HMD162 described above with respect to FIGS. 1A-1B and 2A-2B, respectively.Although particular optical systems are disclosed herein as referenceexamples, the LC patterning control systems disclosed herein maygenerally be included in any suitable optical systems. In variousembodiments, an optical system for an AR, VR, and MR near-eye displaydevice is configured to process virtual-world light, which is generatedby a light source driven by an application (e.g., one of theapplications stored in the application store 355 described above withrespect to FIG. 3) executed by a computer processor. The optical systemmay process such virtual light to form an image at an exit pupil of theoptical system, which may coincide with a location of an eye of a userof the NED device.

In various embodiments, an optical system for an AR and MR near-eyedisplay device is configured to process real-world light. Unlike thecase for virtual-world light, such an optical system need not introduceoptical power to the image of the real-world light at the exit pupil andneed not change the location of the exit pupil for the real-world lightin response to a change in the location (and/or orientation) of the eyewith respect to the optical system. Accordingly, real-world light andvirtual-world light, though co-located in portions of the opticalsystem, are, at least in some embodiments, processed differently fromone another by the optical system.

FIG. 9 is a schematic diagram illustrating a portion of a virtualreality optical system 900 that includes a LC patterning control system,according to various embodiments. For example, the optical system 900could be included in a virtual reality NED. As shown, the optical system900 includes a light source 910 and a LC patterning control system 920.

The light source 910 is configured to project a beam of light onto theLC patterning control system 920. Examples of light sources includeorganic light emitting diodes (OLEDs), active-matrix organiclight-emitting diodes (AMOLEDs), light emitting diodes (LEDs), lasers,superluminescent LED (SLED), or some combination thereof. Anytechnically feasible light source may be used, and the type of lightsource that is used will generally depend on the application. Forexample, a coherent light source, such as a laser or SLED, could be usedto create holograms, while any light source, such as an LED, could beused for normal imaging. In some embodiments, the light source 910 mayproduce polarized light. In other embodiments, the LC patterning controlsystem 920 may include one or more polarization layers that polarizelight from the light source 910 that is incident thereon.

In some embodiments, the LC patterning control system 920 may be one ofthe reflective LC patterning control systems 500, 600, or 700 describedabove with respect to FIGS. 5A-5B, 6A-6B, and 7A-7B, respectively. Forexample, in some embodiments, the LC patterning control system 920 maybe a spatial light modulator including pixels that are driven ON andOFF, thereby forming image(s) reflected toward a viewer. As anotherexample, in some embodiments, the light source 910 may be a coherentlight source, such as a laser, and the LC patterning control system 920may modulate coherent light emitted by the light source 910 to form ahologram. As yet another example, in some embodiments, the LC patterningcontrol system 920 may be used for pupil/beam steering. In such cases,the LC patterning control system 920 could include, e.g., a PBP thatsteers light toward a user's eye.

In some embodiments, the optical system 900 may include additionalcomponents that are not shown, such as a lens or other opticalelement(s) that focus light at an exit pupil 930 of the optical system900, an eye tracking module to provide eye position information to acontroller module, optical element(s) to steer the exit pupil 930 todifferent locations according to an eye gaze angle, etc. For example, arift lens, PBP lens, pancake lens, etc. could be used to focus light atthe exit pupil 930. As another example, an eye tracking module could belocated at any of a number of locations within or on a NED. That is,embodiments may include any technically feasible configuration of a VRoptical system that includes a LC patterning control system according totechniques disclosed herein.

FIG. 10 is a schematic diagram illustrating a portion of another virtualreality optical system 1000 that includes a LC patterning controlsystem, according to various embodiments. For example, the opticalsystem 1000 could be included in a virtual reality NED. As shown, theoptical system 1000 includes a light source 1010 and a LC patterningcontrol system 1020.

Similar to the light source 910 described above, the light source 1010may include, e.g., an OLED, an AMOLED, a LED, a laser, a SLED, or somecombination thereof that projects a beam of light onto the LC patterningcontrol system 1020. Further, in some embodiments, the light source 1010may produce polarized light or, alternatively, the LC patterning controlsystem 1020 may include polarization layer(s) that polarize light fromthe light source 1010.

In contrast to the LC patterning control system 920, the LC patterningcontrol system 1020 transmits light incident thereon from the lightsource 1010. In some embodiments, the LC patterning control system 1020may be the LC patterning control system 800 described above with respectto FIGS. 8A-8B. For example, in some embodiments, the LC patterningcontrol system 1020 may be a spatial light modulator including pixelsthat are driven ON and OFF, thereby forming image(s). As anotherexample, in some embodiments, the LC patterning control system 1020 maymodulate coherent light emitted by the light source 1010 to form ahologram. As yet another example, in some embodiments, the LC patterningcontrol system 1020 may be a PBP optical element, such as a PBP lens orgrating, whose functionalities are discussed in greater detail belowwith respect to FIGS. 12A-12B. As a further example, in someembodiments, the LC patterning control system 1020 may be a varifocallens that has a continuous range of adjustment of optical power enabledby aligning LCs with locally applied magnetic fields.

Similar to the discussion above with respect to the optical system 900,the optical system 1000 may include additional components that are notshown, such as a lens or other optical element(s) that focus light at anexit pupil 1030 of the optical system 1000, an eye tracking module toprovide eye position information to a controller module, opticalelement(s) to steer the exit pupil 1030 to different locations accordingto an eye gaze angle, etc.

FIG. 11 is a schematic diagram illustrating a portion of an augmentedreality optical system 1100 that includes a LC patterning controlsystem, according to various embodiments. For example, the opticalsystem 1100 may be included in an augmented reality NED. The opticalsystem 1100 is different from the optical systems 900 and 1000 in anumber of ways. For example, the optical systems 900 and 1000 areconfigured to operate with virtual-world light, whereas the opticalsystem 1100 is configured to operate with virtual-world light andreal-world light.

As shown, the optical system 1100 includes a light source 1110 and a LCpatterning control system 1120. Similar to the light source 910described above, the light source 1110 may include, e.g., an OLED, anAMOLED, a LED, a laser, a SLED, or some combination thereof thatprojects a beam of light onto the LC patterning control system 1120.Further, in some embodiments, the light source 1110 may producepolarized light or, alternatively, the LC patterning control system 1120may include polarization layer(s) that polarize light from the lightsource 1110.

Illustratively, the LC patterning control system 1120 works in areflective mode that is transparent to real-world light and combines thereal-world light with a virtual image generated using the light source1110. For example, in some embodiments, the LC patterning control system1120 may be the LC patterning control system 800 described above withrespect to FIG. 8. Similar to the discussion above with respect to theLC patterning control system 1020, the LC patterning control system 1120may be, e.g., a spatial light modulator, a PBP optical element, avarifocal lens, or used in holography, among other things, in someembodiments.

In some embodiments, the optical system 1100 may further include aprism, waveguide optical system, or other optical element(s) thatredirect and/or focus light from the light source 1110 to the exit pupilposition 1130. In such cases, a LC patterning control system may (or maynot) be located differently in the optical system than the LC patterningcontrol system 1120 shown in FIG. 11. In some embodiments, the opticalsystem 1100 may also include other components that are not shown, suchas a lens or other optical element(s) that focus light at an exit pupil1130 of the optical system 1100, an eye tracking module to provide eyeposition information to a controller module, optical element(s) to steerthe exit pupil 1130 to different locations according to an eye gazeangle, etc. That is, embodiments may include any technically feasibleconfiguration of an AR optical system that includes a LC patterningcontrol system according to techniques disclosed herein.

FIG. 12A illustrates a PBP grating 1200A, according to variousembodiments. Mutually orthogonal x and y-axes 1210 are illustrated forreference. The z-axis, not illustrated, is perpendicular to the x-yplane and along an optical axis of the grating 1200A.

As shown, the grating 1200A includes uniaxial fast axis 1220 of LC ormeta structure that are oriented in a linearly repetitive pattern. InFIG. 12A, the orientation of the fast axis are illustrated as short linesegments aligned so as to schematically represent orientations of theLCs or the meta structure. For example, the fast axis 1220A is orientedin the x-direction while LC 1220B is oriented in the y-direction. A fastaxis between 1220A and 1220B are aligned along directions intermediateto the x and y-directions. The uniaxial waveplate having such apatterned orientation gives rise to a geometric-phase shift of light asa consequence of polarization evolution as light waves of the lightpropagate through the waveplate (e.g., phase plate). In variousembodiments, orientations of the fast axis along the x-axis are constantfor a particular x-y plane of the grating 1200A. Further, though notillustrated, in various embodiments, orientations of the fast axis in adirection perpendicular to the x-y plane (the z-axis) may vary in arotational fashion (e.g., a twisted structure).

The linearly repetitive pattern of the grating 1200A has a pitch that ishalf the distance 1230 along the y-axis between repeated portions of thepattern. The pitch determines, in part, the optical properties of thegrating 1200A. For example, polarized light incident along the opticalaxis on the grating 1200A results in a grating output comprisingprimary, conjugate, and leakage light respectively corresponding todiffraction orders m=+1, −1, and zero. Although m=+1 is hereinconsidered to be the primary order and the conjugate order is consideredto be the m=−1 order, the designation of the orders could be reversed orotherwise changed. The pitch determines the diffraction angles (e.g.,beam-steering angles) of the light in the different diffraction orders.Generally, the smaller the pitch, the larger the angles for a givenwavelength of light.

FIG. 12B is a top-down view of an example PBP lens 1200B, according tovarious embodiments. Mutually orthogonal x and y-axes 1210 areillustrated for reference. The z-axis, not illustrated, is perpendicularto the x-y plane and along an optical axis of lens 1200B. An r-axis, inthe x-y plane, represents a radial direction and distance from thecenter 1225 of lens 1200B.

As shown, the PBP lens 1200B includes fast axis 1235 that is oriented ina radially and circumferentially repetitive pattern. As shown, the LCsor the meta structures are illustrated as short line segments aligned soas to schematically represent orientations of the fast axis. Forexample, for a fixed distance from the optical axis, the fast axis 1235Ais oriented in a circumferential direction while the fast axis 1235B isoriented in a radial direction. Fast axes between 1235A and 1235B arealigned along directions intermediate to circumferential and radialdirections. As another example, along a fixed radial direction, a fastaxis 1245A is oriented in a circumferential direction while a fast axis1245B is oriented in a radial direction. Fast axes between 1245A and1245B are aligned along directions intermediate to circumferential andradial directions. The uniaxial fast axes of the LCs or meta structureshaving such a patterned orientation give rise to a geometric-phase shiftof light as a consequence of polarization evolution as light waves ofthe light propagate through the geometric phase plate. Though notillustrated, orientations of the fast axis in a direction perpendicularto the x-y plane (the z-axis) may vary in a rotational fashion (e.g., atwisted structure).

The radially repetitive pattern of the lens 1200B has a pitch 1250,which is the distance along the r-axis between repeated portions of thepattern. Generally, the pitch 1250 may vary in a radial direction. Forexample, the distance along the r-axis between repeated portions of thepattern may decrease as r increases. As a result, the pitch 1250 may belarger closer toward the center 1225. The pitch determines, in part, theoptical properties of the lens 1200B. For example, polarized lightincident along the optical axis on the lens 1200B results in a lensoutput of light having a particular focal length for a particularwavelength of light. The pitch determines such a focal length.Generally, the smaller the pitch, the smaller the focal length for agiven wavelength of light.

Classically, a wavefront of light is controlled by adjusting opticalpath length (OPL), defined for an isotropic material as the product ofthe speed of the wave (dependent on the material's refractive index) andthe physical propagation distance of the wave through the material. Fora classical lens, the spatially varying OPL caused by a curved surfaceof a lens results in a phase shift of the wavefront giving rise to afocal length of the lens. A geometric-phase shift of a PBP lens, incontrast, arises from the evolution of lightwaves through theanisotropic volume of the PBP lens. The phase shift depends on thegeometry of the pathway of the individual lightwaves through theanisotropy, which transforms the lightwaves. For example, molecularanisotropy of LCs and nanostructures of meta materials in the PBP lenslead to a phase shift of transmitted or reflected lightwaves. Such aphase shift is directly proportional to the orientation of an effectiveoptic axis and the fast axis orientation of the anisotropic material.

In some embodiments, PBP lenses, such as the PBP lens 1200B may beactive (also referred to as an “active element”) or passive (alsoreferred to as a “passive element”). An active PBP lens, for example,has three optical states: an additive state, a neutral state, and asubtractive state. The additive state adds optical power to the system,the neutral state does not affect the optical power of the system anddoes not affect the polarization of light passing through the active PBPlens, and the subtractive state subtracts optical power from the system.

The state of an active PBP lens may be determined by the handedness ofpolarization of light incident on the active PBP lens and a measure of amagnetic field applied to the active PBP lens made of liquid crystal.For example, in some embodiments, an active PBP LC lens operates in asubtractive state responsive to incident light with a right-handedcircular polarization and an applied magnetic field of zero (or moregenerally, below a threshold magnetic field). In some embodiments, anactive PBP LC lens operates in an additive state responsive to incidentlight with a left-handed circular polarization, and an applied magneticfield of zero. In some embodiments, an active PBP LC lens operates in aneutral state (regardless of polarization) responsive to an appliedmagnetic field. The applied magnetic field aligns LCs with a positivedielectric anisotropy along an applied magnetic field direction. If theactive PBP LC lens is in the additive or subtractive state, then lightoutput from the active PBP LC lens has a handedness that is opposite ofthe handedness of light input into the active PBP LC lens. In contrast,if the active PBP LC lens is in the neutral state, then light outputfrom the active PBP LC lens has the same handedness as the light inputinto the active PBP LC lens.

A passive PBP lens has two optical states: an additive state and asubtractive state. The state of a passive PBP lens is determined by thehandedness of polarization of light incident on the passive PBP lens. Ingeneral, the passive PBP lens outputs light that has a handedness thatis opposite of the light input into the passive PBP lens. For example,in some embodiments, a passive PBP lens operates in a subtractive stateresponsive to incident light with a right handed polarization andoperates in an additive state responsive to incident light with a lefthanded polarization.

In some embodiments, a PBP grating, such as 1200B, may be active (alsoreferred to as an “active element”) or passive (also referred to as a“passive element”). An active PBP grating, for example, has threeoptical states, similar to that of an active PBP lens: an additivestate, a neutral state, and a subtractive state. In an additive state,the active PBP grating diffracts light of a particular wavelength to anangle that is positive relative to the diffraction angle of thesubtractive state. In the subtractive state, the active PBP gratingdiffracts light at a particular wavelength to an angle that is negativerelative to the positive angle of the additive state. On the other hand,in the neutral state, the PBP grating does not lead to a diffraction oflight and does not affect the polarization of light passing through theactive PBP grating.

The state of an active PBP grating may be determined by a handedness ofpolarization of light incident on the active PBP grating and a measureof the magnetic field applied to the active PBP grating. For example, insome embodiments, an active PBP grating operates in a subtractive stateresponsive to incident light with a right-handed circular polarizationand an applied magnetic field of zero (or, more generally, below athreshold magnetic field). In some embodiments, the PBP grating operatesin an additive state responsive to incident light with a left-handedcircular polarization and an applied magnetic field of zero. In someembodiments, the PBP grating operates in a neutral state (regardless ofpolarization) responsive to an applied magnetic field. Liquid crystalswith positive dielectric anisotropy may be aligned along an appliedmagnetic field direction. If the active PBP grating is in the additiveor subtractive state, then light output from the active PBP grating hasa handedness that is opposite the handedness of light input into theactive PBP grating. If the active PBP grating is in the neutral state,then light output from the active PBP grating has the same handedness asthe light input into the active PBP grating.

The state of a passive PBP grating is determined by a handedness ofpolarization of light incident on the passive PBP grating. For example,in some embodiments, a passive PBP grating operates in a subtractivestate responsive to incident light with a right-handed circularpolarization. In some embodiments, the passive PBP grating operates inan additive state responsive to incident light with a left-handedcircular polarization. For the passive PBP grating in the additive orsubtractive state, light output from the passive PBP grating has ahandedness that is opposite the handedness of light input into thepassive PBP grating.

FIG. 13 is a flow diagram illustrating a method for modulating a beam oflight, according to various embodiments. Although the method steps aredescribed with reference to the systems of FIGS. 1-12, persons skilledin the art will understand that any system may be configured toimplement the method steps, in any order, in other embodiments.

As shown, a method 1300 begins at step 1302, where an applicationdetermines the states of pixels of a LC patterning control system for apoint in time. The application may be, e.g., one of the applicationsstored in the application store 355, which as described above withrespect to FIG. 3 may include gaming applications, conferencingapplications, video playback applications, or any other suitableapplications. In some embodiments, the application may determine pixelsof a LC patterning control system to turn ON and OFF at step 1302.Although discussed herein primarily with respect to such systems, theapplication may also determine in-between states in some embodiments.That is, depending on the magnetic field drive system, some or all ofthe intermediate states may be achievable in the LC patterning controlsystem.

The pixel states determined by the application at step 1302 maygenerally depend on the dynamic optics application. For example, theapplication may determine which pixels of a spatial light modulator needto be turned ON or OFF in order to form an image. As another example,the application may solve holography equations in order to determinepixel states needed to generate a hologram from light emitted by acoherent light source. Other pixel states may be determined for otherdynamic optics application.

At step 1304, the application causes liquid crystals associated with thepixels of the LC patterning control system to be driven using magneticfields, based on the determined pixel states. Doing so may reorient theanisotropic molecules of LCs that are associated with pixels to alignwith magnetic fields produced by corresponding magnets. For example, thecontroller could cause currents to be driven through appropriate wiresto switch magnets in the LC patterning control systems 500, 600, and800, as described above with respect to FIGS. 5B, 6B, and 8B,respectively. As another example, the controller could apply voltages todrive currents through the coils of magnets to be switched in the LCpatterning control system 700, as described above with respect to FIG.7B.

At step 1306, the application causes a light beam to be projected ontothe LC patterning control system. The LC patterning control systemimposes a spatially varying modulation on such a light beam. Due tobirefringence, the phase of light passing through LCs will be modulateddifferently for pixels having different states. As a result, the LCpatterning control system may, e.g., form an image, form a hologram fromcoherent light, etc., as described above. In some embodiments, the LCpatterning control system may reflect the modulated light, such as inthe LC patterning control systems 500, 600, and 700 described above withrespect FIGS. 5A-5B, 6A-6B, and 7A-7B, respectively. In otherembodiments, the LC patterning control system may transmit the modulatedlight, such as in the LC patterning control system 800 described abovewith respect to FIGS. 8A-8B.

At step 1308, the application determines whether to continue to anotherpoint in time. If the application determines to continue, then themethod 1300 returns to step 1302, where the application determines thestates of pixels of the LC patterning control system for a next point intime. On the other hand, if the application determines not to continue,then the method 1300 ends.

One advantage of the LC patterning control systems disclosed herein isthat the use of magnetic, rather than electric, fields to align LCspermits pixel sizes to be reduced to below the limit of traditional LCdevices. For example, the pixel sizes of embodiments may be smaller than˜1 μm, such as ˜100 nm. The LC patterning control systems disclosedherein are also not affected by ionic shielding. In addition, themagnetization of anisotropic magnets may be fixed after such magnets areswitched, allowing LCs to remain aligned with magnetic fields producedby those magnets without power dissipation. These technical advantagesrepresent one or more technological advancements over prior artapproaches.

1. Some embodiments include a liquid crystal patterning control system,comprising a plurality of pixels, each of the pixels comprising a liquidcrystal and a magnet, wherein, responsive to a switching of the magnet,molecules of the liquid crystal reorient to substantially align with amagnetic field generated by the magnet.

2. The liquid crystal patterning control system of clause 1, furthercomprising a reflective layer disposed between the liquid crystal andthe magnet included in each of the pixels, wherein the reflective layeris configured to reflect light that is incident on the liquid crystalpatterning control system and modulated by the liquid crystals includedin the pixels.

3. The liquid crystal patterning control system of any of clauses 1-2,wherein the magnet included in each of the pixels comprises amicroparticle, a nanoparticle, or a plurality of magnetic domains.

4. The liquid crystal patterning control system of any of clauses 1-3,further comprising a plurality of wires disposed in a cross-wireconfiguration below the magnets included in the pixels, wherein each ofthe magnets included in the pixels is switched by driving currentthrough corresponding wires.

5. The liquid crystal patterning control system of any of clauses 1-4,wherein the magnet included in each of the pixels comprises a differentmicrocoil or nanocoil wrapped around a high permeability core, and eachmicrocoil or nanocoil included in the pixels is connected to acorresponding voltage source and a common ground.

6. The liquid crystal patterning control system of any of clauses 1-5,wherein the magnet included in each of the pixels is wrapped around theliquid crystal included in the pixel.

7. The liquid crystal patterning control system of any of clauses 1-6,wherein each of the pixels further comprises at least one alignmentlayer disposed adjacent to the liquid crystal included in the pixel, andthe at least one alignment layer included in each of the pixelssubstantially aligns molecules of the liquid crystal included in thepixel prior to switching of the magnet associated with the liquidcrystal.

8. The liquid crystal patterning control system of any of clauses 1-7,wherein the liquid crystal patterning control system includes one of aspatial light modulator, a Pancharatnam-Berry phase lens, a liquidcrystal display screen, or a varifocal lens.

9. The liquid crystal patterning control system of any of clauses 1-8,wherein the liquid crystal patterning control system is used incomputer-generated holography.

10. The liquid crystal patterning control system of any of clauses 1-9,wherein the liquid crystal patterning control system is included in anear eye display device.

11. Some embodiments include a cell, comprising a birefringent material,and at least one alignment layer disposed adjacent to the birefringentmaterial, wherein an reorientation of molecules in the birefringentmaterial is driven by a magnet.

12. The cell of clause 11, wherein a reflective layer is disposedbetween the birefringent material and the magnet.

13. The cell of any of clauses 11-12, further comprising at least one ofa glass substrate layer or a polarization layer.

14. The cell of any of clauses 11-13, wherein the birefringent materialcomprises liquid crystal molecules in a planar or homeotropic alignment,and responsive to a switching of the magnet, the liquid crystalmolecules included in the birefringent material reorient tosubstantially align with a magnetic field generated by the magnet.

15. The cell of any of clauses 11-14, wherein the magnet comprises amicroparticle, a nanoparticle, a plurality of magnetic domains, ormicrocoil or nanocoil wrapped around a high permeability core.

16. The cell of any of clauses 11-15, wherein the magnet is wrappedaround the birefringent material.

17. Some embodiments include a computer-implemented method formodulating light, the method comprising determining states of aplurality of pixels for at least one point in time, driving liquidcrystals associated with the pixels using magnetic fields, based on thedetermined states of the pixels, and projecting light that passesthrough the liquid crystals.

18. The method of clause 17, further comprising, reflecting the lightthat passes through the liquid crystals.

19. The method of any of clauses 17-18, wherein driving the liquidcrystals comprises either causing currents to be driven through wiresthat intersect at magnets associated with the liquid crystals orapplying voltages to the magnets associated with the liquid crystals.

20. The method of any of clauses 17-19, wherein the light is associatedwith an artificial reality application.

Any and all combinations of any of the claim elements recited in any ofthe claims and/or any elements described in this application, in anyfashion, fall within the contemplated scope of the present disclosureand protection.

The foregoing description of the embodiments of the disclosure has beenpresented for the purpose of illustration; it is not intended to beexhaustive or to limit the disclosure to the precise forms disclosed.Persons skilled in the relevant art can appreciate that manymodifications and variations are possible in light of the abovedisclosure.

Some portions of this description describe the embodiments of thedisclosure in terms of algorithms and symbolic representations ofoperations on information. These algorithmic descriptions andrepresentations are commonly used by those skilled in the dataprocessing arts to convey the substance of their work effectively toothers skilled in the art. These operations, while describedfunctionally, computationally, or logically, are understood to beimplemented by computer programs or equivalent electrical circuits,microcode, or the like. Furthermore, it has also proven convenient attimes, to refer to these arrangements of operations as modules, withoutloss of generality. The described operations and their associatedmodules may be embodied in software, firmware, hardware, or anycombinations thereof.

Any of the steps, operations, or processes described herein may beperformed or implemented with one or more hardware or software modules,alone or in combination with other devices. In one embodiment, asoftware module is implemented with a computer program productcomprising a computer-readable medium containing computer program code,which can be executed by a computer processor for performing any or allof the steps, operations, or processes described.

Embodiments of the disclosure may also relate to an apparatus forperforming the operations herein. This apparatus may be speciallyconstructed for the required purposes, and/or it may comprise ageneral-purpose computing device selectively activated or reconfiguredby a computer program stored in the computer. Such a computer programmay be stored in a non-transitory, tangible computer readable storagemedium, or any type of media suitable for storing electronicinstructions, which may be coupled to a computer system bus.Furthermore, any computing systems referred to in the specification mayinclude a single processor or may be architectures employing multipleprocessor designs for increased computing capability.

Embodiments of the disclosure may also relate to a product that isproduced by a computing process described herein. Such a product maycomprise information resulting from a computing process, where theinformation is stored on a non-transitory, tangible computer readablestorage medium and may include any embodiment of a computer programproduct or other data combination described herein.

Finally, the language used in the specification has been principallyselected for readability and instructional purposes, and it may not havebeen selected to delineate or circumscribe the inventive subject matter.It is therefore intended that the scope of the disclosure be limited notby this detailed description, but rather by any claims that issue on anapplication based hereon. Accordingly, the disclosure of the embodimentsis intended to be illustrative, but not limiting, of the scope of thedisclosure, which is set forth in the following claims.

The descriptions of the various embodiments have been presented forpurposes of illustration, but are not intended to be exhaustive orlimited to the embodiments disclosed. Many modifications and variationsis apparent to those of ordinary skill in the art without departing fromthe scope and spirit of the described embodiments.

Aspects of the present embodiments may be embodied as a system, method,or computer program product. Accordingly, aspects of the presentdisclosure may take the form of an entirely hardware embodiment, anentirely software embodiment (including firmware, resident software,micro-code, etc.) or an embodiment combining software and hardwareaspects that may all generally be referred to herein as a ““module” or“system.” Furthermore, aspects of the present disclosure may take theform of a computer program product embodied in one or more computerreadable medium(s) having computer readable program code embodiedthereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

Aspects of the present disclosure are described above with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of thedisclosure. It is understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine. The instructions, when executed via the processor ofthe computer or other programmable data processing apparatus, enable theimplementation of the functions/acts specified in the flowchart and/orblock diagram block or blocks. Such processors may be, withoutlimitation, general purpose processors, special-purpose processors,application-specific processors, or field-programmable gate arrays.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present disclosure. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

While the preceding is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A liquid crystal patterning control system,comprising: a plurality of pixels, each of the pixels comprising: aliquid crystal, and a magnet, wherein, responsive to a switching of themagnet, molecules of the liquid crystal reorient to substantially alignwith a magnetic field generated by the magnet, and wherein the magnet isswitchable between a plurality of preferred magnetization directions ora plurality of magnetic domains, wherein each of the plurality ofpreferred magnetization directions or the plurality magnetic domainscorresponds to a different state of the pixel.
 2. The liquid crystalpatterning control system of claim 1, further comprising: a reflectivelayer disposed between the liquid crystal and the magnet included ineach of the pixels, wherein the reflective layer is configured toreflect light that is incident on the liquid crystal patterning controlsystem and modulated by the liquid crystals included in the pixels. 3.The liquid crystal patterning control system of claim 1, wherein themagnet included in each of the pixels comprises a microparticle or ananoparticle.
 4. The liquid crystal patterning control system of claim3, further comprising: a plurality of wires disposed in a cross-wireconfiguration below the magnets included in the pixels, wherein each ofthe magnets included in the pixels is switched by driving currentthrough corresponding wires.
 5. The liquid crystal patterning controlsystem of claim 1, wherein: the magnet included in each of the pixelscomprises a different microcoil or nanocoil wrapped around a highpermeability core; and each microcoil or nanocoil included in the pixelsis connected to a corresponding voltage source and a common ground. 6.The liquid crystal patterning control system of claim 1, wherein: eachof the pixels further comprises at least one alignment layer disposedadjacent to the liquid crystal included in the pixel; and the at leastone alignment layer included in each of the pixels substantially alignsmolecules of the liquid crystal included in the pixel prior to switchingof the magnet associated with the liquid crystal.
 7. The liquid crystalpatterning control system of claim 1, wherein the liquid crystalpatterning control system includes one of a spatial light modulator, aPancharatnam-Berry phase lens, a liquid crystal display screen, or avarifocal lens.
 8. The liquid crystal patterning control system of claim1, wherein the liquid crystal patterning control system is used incomputer-generated holography.
 9. The liquid crystal patterning controlsystem of claim 1, wherein the liquid crystal patterning control systemis included in a near eye display device.
 10. A cell, comprising: abirefringent material; and at least one alignment layer disposedadjacent to the birefringent material, wherein a reorientation ofmolecules in the birefringent material is driven by a magnet, andwherein the magnet is switchable between a plurality of preferredmagnetization directions or a plurality of magnetic domains.
 11. Thecell of claim 10, further comprising a reflective layer that is disposedbetween the birefringent material and the magnet.
 12. The cell of claim10, further comprising at least one of a glass substrate layer or apolarization layer.
 13. The cell of claim 10, wherein: the birefringentmaterial comprises liquid crystal molecules in a planar or homeotropicalignment; and responsive to a switching of the magnet, the liquidcrystal molecules included in the birefringent material reorient tosubstantially align with a magnetic field generated by the magnet. 14.The cell of claim 10, wherein the magnet comprises a microparticle, ananoparticle, or a microcoil or a nanocoil wrapped around a highpermeability core.
 15. A computer-implemented method for modulatinglight, the method comprising: determining states of a plurality ofpixels for at least one point in time; driving, based on the determinedstates of the pixels, liquid crystals associated with the pixels usingmagnets associated with the liquid crystals, wherein each magnetassociated with one of the liquid crystals is switchable between aplurality of preferred magnetization directions or a plurality ofmagnetic domains; and projecting light that passes through the liquidcrystals.
 16. The method of claim 15, further comprising, reflecting thelight that passes through the liquid crystals.
 17. The method of claim15, wherein driving the liquid crystals comprises either causingcurrents to be driven through wires that intersect at magnets associatedwith the liquid crystals or applying voltages to the magnets associatedwith the liquid crystals.
 18. The method of claim 15, wherein the lightis associated with an artificial reality application.